solar neutrino results
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Solar Neutrino Results. Tadao Mitsui Research Center for Neutrino Science, Tohoku University. July 26, 2004 6th International Workshop on Neutrino Factories & Superbeams. Osaka University, Osaka, Japan. Solar and reactor neutrinos. Results from Super-Kamiokande and SNO - PowerPoint PPT PresentationTRANSCRIPT
Solar Neutrino Results
Tadao Mitsui Research Center for Neutrino Science, Tohoku University
July 26, 20046th International Workshop on Neutrino Factories & Superbeams
Osaka University, Osaka, Japan
Solar and reactor neutrinos
• Results from Super-Kamiokande and SNO
• Reactor results from KamLAND
• Radiochemical results and earlier works
• Near future prospects
(*1)
(*2)
(*1) neutrinograph of the sun by Super-K, (*2) hep-ph/0406294
Chlorine (1964 ~ 1994)
• First solar neutrino observation• Established solar neutrino deficit• 615-ton C2Cl4, e(37Cl, 37Ar)e-
• Final result: 2.56 ± 0.16 ± 0.16 SNU
• SSM (BP04) expectation: 8.5 1.8 SNU• Data/SSM = 0.30 ± 0.03 Still important input in the current
global analysis for solar neutrino
SSM BP04: J.N. Bahcall and M.H. Pinsonneault PRL 92, 121301
0.813 MeV
8B, 7Be
SNU: 1 interaction / sec each 1036 target atoms
Kamiokande (1987 ~ 1995)
• First measurement of time, direction, energy of solar-
• Data/SSM=0.55 ± 0.04 ± 0.07• Upgraded to Super-K
PRD 44 (1991) 2241
7 MeV
8B
Gallium experiments
• Sensitive to pp neutrino (main component of solar-)• e(71Ga, 71Ge)e-
• 68.1 ± 3.75 SNU (GALLEX + GNO + SAGE)• SSM (BP04): 131+12
-10 SNU• Data / SSM = 0.52 ± 0.03
0.233 MeV
pp, 7Be, 8B
(*1) C.M. Cattadori, Neutrino 2004
new results (*1)
Four solutions that were allowedonly with fluxes (Cl, Ga, Kamiokande)
(LMA) Mikheyev-Smirnov- Wolfenstein (MSW)
~106 range in m2
Super-Kamiokande (1996 ~ ) • 50 kton water cherenkov• 22.5 kton fiducial• ~ 15 events / day (> 5 MeV) ( 8B, (hep) )
+ e- + e-
well remembers energy, direction
Super-Kamiokande-I (1496 days)
M. Nakahata, Neutrino 2004, PLB 539, 179
May 31, 1996 - July 13, 2001
Super-Kamiokande-I (1496 days)
M. Nakahata, Neutrino2004, PLB 539, 179
May 31, 1996 - July 13, 2001
SK-I: energy and zenith angle 2-D spectrum“zenith spectrum”
Excluded without8B flux (rate)
PLB 539, 179
Allowed(with SSM 8B flux)
SMA, Just-so: excluded by energy spectrum
LOW, LMA: constrained by day/nightExpected “regeneration” of e during night: too largecompared with the data
• Asdf
Only LMA at 98% C.L.
PLB 539, 179
May 2002
Ga + Cl + SK + SNO rates + SK zenith spectrum
Sudbury Neutrino Observatory (SNO)1999 ~
1000 ton D2O
12-m diameteracrylic vessel
1700 ton H2O
Support structurefor 9500 8-inch PMTs
5300 ton outer H2O
• CC = e
• NC = e + +
= (all active )• ES = e
+ 0.154 ( + )
• Determine e, + 1 redundancy
e + d p + p + e-
e + d p + n +
e + e- e + e-
CC: charged current
NC: neutral current
ES: elastic scattering (also SK)
n + d 3He + 6.25-MeV (phase I)
energy,(direction)
energy,direction
Unique sensitivity to neutrino flavor
Results: extraction of 3 reactions
CC: 1967.7+61.9 eventsNC: 576.5+49.5 eventsES: 263.6+26.4 events
cos sun
Vertex Energy
PRL 89, 011301, results from 306.4 days
- 25.6
- 48.9
- 60.9
SK-ES + SNO-CC: 3.3
PRL 87(2001), 071301
SK-ES + SNO-CC,NC,ES: 5.5 PRL 89(2002), 011301
With SNO-phse-II (salt) dataM. Nakahata, NOON2004
Evidence for flavor transformation
Significance for non-zero
BP04 = 5.79 (±23%)
SSM “verified”
Deduced “appearance”
Only LMA at 99.5% C.L.
-ADN = 7.0 % 4.9% %+1.3- 1.2
July 2002
PRL 89, 011302
SNO day/night spectra + all solar
from day/night spectral shape analysis
• Reactor e experiment• To reach solar- solution 100 improvement on m2 sen
sitivity
1100
ChoozPalo Verde
100
LMA
A. Suzuki, Neutrino 98
KamLAND
Powerful commercial reactors
First results from KamLANDPRL 90, 021802
e disappearance:99.95 % C.L.
Dec. 2002
Impact of KamLAND
assuming CPT invariance
http://hitoshi.berkeley.edu/neutrino/
LMA-I and LMA-IIfrom spectral shape analysis
95 % C.L.
PRL 90, 021802
LMA-II:m2~1510-5 eV2
LMA-I:m2~710-5 eV2
LMA: precise studySK-I reanalysis: un-binned (time, energy)
• To use all information of zenith angle dependence during night
• Un-binned maximum likelihood method for time and energy
PRD 69, 011104 (R)
m2=6.310-5 eV2, tan2=0.55
Sept. 2003
Consistent results
Binned (PLB 539, 179)
Un-binned (PLD 69, 011104)
Day/night: statistical error 25% reduced
Binned (PLB 539, 179) Un-binned (PLD 69, 011104)
ADN = - 2.1 % 2.0% %+1.3- 1.2 ADN = - 1.8 % 1.6% %
+1.3- 1.2
(at best fit LMA)
LMA-I LMA-II
expected
observed(± 1)
LMA-II disfavored
After SK un-binned analysisLMA-II is excluded at >95 % C.L.
Sept. 2003All solar
M. Nakahata, Neutrino 2004
All solar + KamLAND 1st result
PRD 69, 011104 (R)
95% C.L. allowed
SNO enhanced neutral current (salt) phase
Single cherenkov ringIsotropic event
Sept. 2003
e + d p + n +
NC: neutral current
n + d 3He + 6.25-MeV
n6 MeV)
Phase-I (Nov. 99 - May 01)
e + d p + n +
n + 35Cl 36Cl + 8.6-MeV ’s
Phase-II (July 01 - Sep 03)
2 ton NaCl dissolved
PRL 92, 181301
Total eff. 39.9%
14.4%(phase-I)
Energy spectra: not assumed but measured
cos sun
Vertex Energy
Isotropy
Not usedto extractreactions
CC / NC = e / active
without assuming 8B spectral shape
CC/NC1.0
0.5
1.0
SNO salt result
No oscillation
Maximal mixing
Maximal mixingexcluded at 5.4
After SNO-salt,LMA-II is excluded at >99%
PRL 92, 181301
LMA-II3
SNO CC/NC disfavors LMA-II, and also maximal-mixing
hep-ph/0309299P.C. Holanda & A.Yu. Smirnov
SNO salt result(CC/NC=0.306)
LMA-II
Maximal mixing
KamLAND: 2nd reactor results with 4.7 data
A. Kozlov (Working Group 1)hep-ex/0406035
All flux free parameter
Verification of standard solar modelJ.N. Bahcall, M.C. Gonzalez-Garcia, C. Pena-Garay, hep-ph/0406294
90, 95,99%, 3
90, 95,99%, 3
All flux BP04
Verification of standard solar modelJ.N. Bahcall, M.C. Gonzalez-Garcia, C. Pena-Garay, hep-ph/0406294
90, 95,99%, 3
95,99%, 3
KamLANDglobal analysis
Oscillation: robust against solar model
• Without KamLAND, and GNO new results:fpp = 1.02 ± 0.02 (1)
fB = 0.88 ± 0.04
fBe = 0.91 + 0.25 / - 0.62
• With KamLAND, and GNO new results:fpp = 1.01 ± 0.02
fB = 0.87 ± 0.04
fBe = 1.03 + 0.24 / - 1.03
flux at productionSolar neutrino measurement
hep-ph/0406294
f “measured” / SSM(BP04)
Small differencedespite KamLANDnew result
Solar-: robust against neutrino oscillation
• 3He proportional counter: to detect n from NC
• Event-by-event separation• Better CC energy spectrum
J.F. Wilkerson, Neutrino 2004
Near future: SNO 3He phase
• All 40 3He strings installed (April, 2004)• Will run for 2.5 years 2 precision of present SNO result
J.F. Wilkerson, Neutrino 2004Near future: SNO 3He phase
• 11,146 PMTs with protection cases
• Full reconstruction from 2005 (plan)
• SK-III from ~2006Acrylic + FRP cases
Near future: full reconstruction of SK
Near future: full reconstruction of SK
M. Nakahata, Neutrino 2004
Toward 7Be solar- observation
C. Galbiati, Neutrino 2004Near future: Borexino
• 210Pb: ~105 reduction needed• R&D almost finished: achieved ~104 reductio
n with test bench• SiO2 adsorption:
achieved 95% reduction• Complex purification sy
stem
Near future: KamLAND-II
Toward 7Be solar- observation
• Solar neutrino oscillation: MSW-LMA is the solution– m2 = 8.2 +0.6
-0.5 10-5 eV2
tan2 = 0.40 +0.09-0.07 (a global analysis by KamLAND)
• Standard solar model verified with 5% accuracy (8B)• Further precise study in the near future (SNO 3He, SK-III, Borexino, KamLAND-II etc) solar astrophysics, search for new phenomen
a
Summary